1. Field of the Invention
The present invention relates to novel tomato products having an improved saucing power in particular on pasta.
2. Description of the Related Prior Art
Tomato products, prepared from the tomato juice obtained by fruit trituration, seed and peel separation, are known in the prior art. The tomato juice is an aqueous suspension of insoluble solids in an aqueous solution wherein organic and inorganic substances are dissolved.
From the obtained juice other products such as tomato passatas and tomato concentrates can be obtained. Tomato passatas in general are obtained from juices by partial concentration. The tomato concentrates are obtained by stronger concentration processes. The methods generally used are the reverse osmosis, cryoconcentration and concentration by evaporation. By using the reverse osmosis it is not possible to operate at room temperature. Temperatures of about 70° C. are requested in order to have a satisfactory concentration yield; furthermore it is necessary to clean and regenerate the membranes by means of chemical detergents, which must then be removed. In fact said compounds are pollutant of the tomato products. See C. S. Leoni “I derivati industriali del pomodoro”, experimental Station for the food preserves industry in Parma, October 1993, pages 92-93. The cryoconcentration is inapplicable to the tomato juice due to the high percentage of solids in suspension, which would be separated together with ice. See page 93 of the previous quotation.
In practice the concentration by evaporation remains the method of choice to concentrate the tomato juice. See page 93 of the previous reference. Concentration by evaporation implies juice heating; the duration of heating and the maximum temperature reached in the juice during the concentration step lead to organoleptic and nutritional variations of the product. The organoleptic variations are a caramel taste and a typical cooking (“cotto”) aroma present in tomato concentrates and they are mainly due to the formation during juice concentration of hydrogen sulphide, dimethylsulphide, furfural, 3-methylmercaptopropanal, 2,4-heptadienal, acetaldehyde, phenylacetaldehyde. See S. Porretta “Il controllo della qualità dei derivati del pomodoro”, experimental Station for the food preserves industry in Parma (1991), page 51; S. J. Kazeniac et al., J. Food Sci. 35 519 (1970).
The nutritional variations are mainly due to the degradation of the carotenoids present in the tomato and in particular of lycopene. The tomato as such and its products have a high nutritional value, deriving from the vitaminic components, and mainly from the contained carotenoids. It has been demonstrated that the tomato product consumption is associated to a risk decrease of some cancer types (prostata, pancreas, stomach). See H. Gerster, J. Am. Coll. Nutr. 1997, 16, 109-126; S. K. Clinton Nutr. Rev. 1998 56 35-51. The previously described beneficial nutritional effects are to be ascribed to the carotenoids contained in the tomato and in particular to lycopene. Recently it has been shown that during the concentration by evaporation of the tomato juice there is a degradation of carotenoids, lycopene too. See R. Gary et al., J. Agric. Food Chem. 2001 49 3713-3717.
It is also known that it is not feasible to filter the tomato products, in particular tomato juices and tomato passatas, since the filter is quite immediately occluded.
Most of the commercial tomato products must be diluted before use. The commercial tomato concentrates, for example in Italy, are classified as follows:
semiconcentratedry residue 12% by weight;concentrate (C)dry residue 18% by weight;double concentrate (DC)dry residue 28% by weight;triple concentrate (TC)dry residue 36% by weight.
Generally the concentrated products are diluted before and during the use. The saucing power of the triple concentrate (TC) as such, before dilution, is higher than that of the other commercial tomato products, concentrates included. By saucing power it is meant the product capability to stick to foods to which it is added, for instance pasta. However, as above mentioned, said concentrated products must be diluted before or during use because of their too strong and unpleasant taste. Consequently the advantage of the higher saucing power of said products is lost. Generally all the commercial tomato concentrates having a dry residue above 12% wt. show such taste problem and therefore must be diluted.
If a semiconcentrate at 12% dry residue is used, since it generally should not be diluted before use showing no problems of unpleasant taste, the saucing power is very low, even lower than the saucing power of TC as such. The tomato products known as tomato passatas are used as a ready base for quick sauce preparation. Generally in tomato passatas the dry residue, which can be determined as described afterwards, is lower than or equal to 10% by weight, generally comprised between 8%-10% by weight.